3D PRINTING OF BUILDING ELEMENTS AND BUILDINGS WITH BCT CEMENT

Abstract

The present invention relates to the use of belite calcium sulfoaluminate ternesite cement for the production of components and buildings by means of 3D printing and a method for the production of components and buildings by the 3D printing of belite calcium sulfoaluminate ternesite cement.

Claims

1. A use of belite calcium sulfoaluminate ternesite cement as a building material for the production of building elements and buildings by means of 3D printing.

2. Use according to claim 1, wherein the belite calcium sulfoaluminate ternesite cement contains 5 to 75% by weight C.sub.5S.sub.2$ 5 to 70% by weight C.sub.4A.sub.3$ 1 to 80% by weight C.sub.2S and 0 to 30% by weight secondary phases wherein the total of all phases contained is 100% by weight.

3. The use according to claim 1, wherein the secondary phases in belite calcium sulfoaluminate ternesite cement are one or more of calcium silicates, sulphates, calcium aluminates, spinels, representatives of melilite group, periclase, free lime, quartz and/or a glass phase.

4. The use according to claim 1, wherein the secondary phases are present in a proportion of 0.1% by weight to 30% and particularly preferred from 10% by weight to 15% by weight.

5. The use according to claim 1, wherein the belite calcium sulfoaluminate ternesite cement contains 10-60% by weight, in particular 20-40% by weight C.sub.5S.sub.2$, 10-60% by weight, in particular 20-45% by weight C.sub.4A.sub.3$ and 10-65% by weight, in particular 20-50% by weight C.sub.2S.

6. The use according to claim 1, wherein at the free lime content in the belite calcium sulfoaluminate ternesite cement is below 5% by weight, in particular below 2% by weight and most preferably below 1% by weight.

7. The use according to claim 1, wherein there is an X-ray amorphous phase or glass phase in an amount of 1 to 10% by weight, preferably 2 to 8% by weight and in particular 3 to 5% by weight in the belite calcium sulfoaluminate ternesite cement.

8. A Method for the production of building elements and buildings, wherein: a belite calcium sulfoaluminate ternesite cement is provided, the belite calcium sulfoaluminate ternesite cement is mixed with aggregate and water to form a building material, and the building material is formed layer by layer into the building element or building arranged using a 3D printer.

9. The Method according to claim 8, wherein sand and/or crushed sand and/or gravel and/or crushed rocks and/or recycled aggregates of natural origin and/or from industrial production with a particle size of up to 32 mm, preferably up to 8 mm, in particular up to 4 mm are used as aggregate.

10. The Method according to claim 8, wherein a weight ratio is set in the building material of belite calcium sulfoaluminate ternesite cement to aggregate in the range from 1:2 to 1:8, preferably from 1:3 to 1:5.

11. The Method according to claim 8, wherein a water/cement value is set in the building material in the range from 0.25 to 0.8, preferably from 0.3 to 0.5.

12. The Method according to claim 8, wherein at least one of a supplementary cementitious material, admixture and additive is added to the building material.

13. The Method according to claim 12, wherein supplementary cementitious materials such as fly ash, granulated slag and/or microsilica are added to the building material, preferably at a weight ratio of belite calcium sulfoaluminate ternesite cement:supplementary cementitious material in the range from 1:0.7 to 1:0.1, in particular from 1:0.3 to 1:0.2.

14. The Method according to claim 12, wherein retarding admixtures, preferably gluconates, fruit acid, phosphates, phosphonates or borates as well as mixtures thereof and, in particular, phosphates, phosphonates or borates as well as mixtures thereof, are added to the building material.

15. The Method according to claim 12, wherein fibres, in particular made from steel, plastic, glass and/or carbonate, are added to the building material as additives.

16. The Method according to claim 12, wherein one or more concrete pigments and/or photocatalysts are added to the building material as additives.

17. The Method according to claim 8, wherein the belite calcium sulfoaluminate ternesite cement is provided by mixing calcium sulfoaluminate cement and ternesite cement, which was obtained by sintering raw meal made from raw materials providing at least CaO and SiO.sub.2 at temperatures of 900 to 1300 C.

18. The Method according to claim 8, wherein the belite calcium sulfoaluminate ternesite cement is provided by grinding a belite calcium sulfoaluminate ternesite clinker, wherein the belite calcium sulfoaluminate ternesite clinker is obtained by sintering raw meal made from raw materials providing at least CaO, SiO.sub.2 and Al.sub.2O.sub.3 in a temperature range from >1200 C. to 1350 C., tempering a clinker intermediate product thereby obtained in a temperature range from 1200 C. to a lower limit of 750 C. to form the belite calcium sulfoaluminate ternesite clinker and cooling the belite calcium sulfoaluminate ternesite clinker.

Description

EXAMPLE 1

[0059] The start and end of setting according to DIN EN 196 part 3 and strengths after 1, 2, 7, 28 and 90 days according to DIN EN 196 part 1 were determined on two sample series for a BCT cement. The BCT cement had the following composition according to X-ray fluorescence analysis:

TABLE-US-00002 Component Weight [% by weight] Ignition loss 1.01 SiO.sub.2 17.95 Al.sub.2O.sub.3 15.58 TiO.sub.2 0.60 MnO 0.04 Fe.sub.2O.sub.3 3.23 CaO 51.48 MgO 0.96 K.sub.2O 0.68 Na.sub.2O 0.12 SO.sub.3 7.16 P.sub.2O.sub.5 0.21 Total 99.1
The main phases were 24.8% by weight ye'elimite (C.sub.4A.sub.3$), 52.4% by weight belite (-C.sub.2S) and 8.7% by weight ferrites (C.sub.4AF/C.sub.2F). The cement was mixed with sand in accordance with DIN EN 196 part 1 at a ratio of 1:3 and the mixture was mixed with water at a ratio of cement:water of 1:0.5.

[0060] The start of setting was at 20 minutes and the end of setting at 30 minutes. The measured compressive strengths are shown in FIG. 1. Two series were measured, each with three samples, such that each of the two displayed values for one point in time represents an average of 6 measurements.

[0061] The measured strengths show that, even without the addition of retarding or accelerating admixtures, sufficient strength is achieved quickly and the final strength results in statically stable building elements or buildings even without reinforcement or other measures.